There is a need for a device that allows one-handed precision measurements to be performed while the item being measured is also marked with one hand. The common measuring tape, commonly used in construction, for which the inventive improvement is proposed, has evolved over the last one hundred years into an easily operated tool familiar to millions of people. Its use, however, requires the use of two hands, one for holding the measuring tape and the other for marking the item being measured.
As is well known, typical prior art measuring tape devices have a measuring tape element, which is rolled up and enclosed in a standard rectangular case. The tape is rolled up inside the case with one of its two ends affixed inside the case to prevent it from slipping out. The second, free end of the tape element is capped by a lip and used to hook the tape element to edges of surfaces being measured. The lip also functions to prevent the second end from being pulled inside the case. The tape element is marked with markings having associated numbers which indicate the exact distance from the markings to the lip. The case has a case surface from which the tape protrudes, and a surface on which the hold/release knob is located. The hold/release knob permits the tape element to unroll, roll up, or be held in place while in the unrolled state.
Numerous unsuccessful attempts have been made to improve the measuring tape 50 to enable making measurements with one hand. For example, U.S. Pat. No. 5,154,006 adds to a standard measuring tape 50 a clip for holding a pencil which can be used to make markings after a surface distance has been measured. This approach is supposed to allow a workman to make a measurement and leave a mark using only one hand. However, because of the free movement of the clipped pencil, the measurement itself is not precise and the pencil is not safe from breakage if kept with other tools as is commonly done.
An attempted improvement on the above design was made in the U.S. Pat. No. 5,671,543, wherein the pencil could be affixed to the measuring tape 50 in such a way that it will not be moved by a slight force. The problem with this approach is that it was designed for a carpenter's pencil which is quite large, and thus the whole device is bulky because the structure holding the pencils is also quite large. Holding the device is also uncomfortable and the storage of such device with other tools would usually either break the pencil or break the marking tip off of the pencil. Additional time would be required either to sharpen the pencil or to replace it. If the pencil breaks as it is being used, the workman will have to stop all work and use two hands to move the pencil to its proper position.
U.S. Pat. No. 4,542,589 offers a solution to the problem of the pencil size by putting it inside the casing of the measuring tape 50. However, the marking pencil is located in such a way so as to force the workman to bend the measuring tape 50 every time the mark is to be made. Bending increases the wear and tear on the measuring tape 50. The measuring tape 50 can easily be bent over or under the location of the wanted mark; therefore, the precision of the measurement can not be guaranteed. Moreover, valuable time must be wasted when the workman is forced to repeat the marking step over and over until the correct mark is found.
Finally, U.S. Pat. No. 4,760,648 adds a clip to a standard tape measure 1, which holds a pencil on a support which is secured to one side of the tape measure housing. This pencil and support extend from the standard tape measure 1 and therefore can be easily bent and damaged when stored with other tools. This would easily cause the loss of precision of the measurement and unnecessarily waste time in fixing the pencil. The pencil can neither be fixed nor placed in a proper position with only one hand.
Therefore, the invention overcomes the various problems of the prior art by providing a device that allows the workman to make measurements, with a precision measuring to the smallest fraction increment on the tape of the tape measuring device. That device, furthermore, should not lose its precision with common wear and tear of the measuring tape 50 or increase the wear and tear on the tape by forcing a bending of the tape, and allow the measurements to be achieved and the measured surface to be marked with one hand. The invention can also enable all the marking and cutting elements to be more flush and integrated into a tape measure case than is known.
It is also the purpose of this invention to retrofit existing measuring tapes 50 purchased by millions of people and allow those measuring tape devices to be used as described above for making precise measurements while using only one hand, by using the additional embodiment with a shell casing which encloses a standard tape measure 1.